thats normal to see precum on the tip of your penis and to see it come out into your urine stream, and once you get done shaking after urinating you will see precum as well because it being a clear slimy fluid. i think it all depends how stimulated u get. its normal to if it gets on your boxers, underwear,etc. somedays u may have more then other days, it depends on how excited u get. i wouldnt worry about it all. i think its normal